Manufacturing method of matte polyester film

Abstract

To provide a matte polyester film and a method for producing the same.SOLUTION: There is provided a method for producing a matte polyester film which comprises: supplying a recycled polyester material; physically recycling a portion of the recycled polyester material to form physically recycled polyester chips having a first intrinsic viscosity; chemically recycling another portion of the recycled polyester material to form chemically recycled polyester chips having a second intrinsic viscosity less than the first intrinsic viscosity; mixing matte recycled polyester chips, physically recycled polyester chips and the chemically recycled polyester chips according to a predetermined viscosity to form a polyester master batch material; and dissolving and extruding the polyester master batch material to obtain a matte polyester film having a predetermined intrinsic viscosity.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to matte polyester films and methods for making the same, and more particularly to matte polyester films prepared using both physically recycled and chemically recycled polyester resins and methods for making the same. [Background technology]

[0002] In the prior art, the most common method for recycling waste PET bottles is the physical recycling method (or mechanical recycling method). The physical recycling method mainly involves crushing the waste PET bottle material by physical and mechanical means, then placing the crushed PET bottle material in a high-temperature environment for melting, and then pelletizing the melted PET bottle material to form physically recycled polyester chips. The physically recycled polyester chips can be used in subsequent processing operations.

[0003] Physically regenerated polyester chips produced by physical recycling methods usually have a high intrinsic viscosity (IV). Solid-state polymerization is mainly used to adjust the intrinsic viscosity of physically regenerated polyester chips. However, the solid-state polymerization method can only be used to increase the intrinsic viscosity of physically regenerated polyester chips, but cannot be used to decrease the intrinsic viscosity of physically regenerated polyester chips. In addition, common film-forming processes usually have a specific limit on the intrinsic viscosity range of polyester chips. Physically regenerated polyester chips produced by physical recycling methods are usually only suitable for bottle blowing and spinning processes, but not for film extrusion.

[0004] In order to make physically recycled polyester chips suitable for film-forming processing, the physically recycled polyester chips are mainly mixed with additional virgin polyester chips to reduce the overall intrinsic viscosity of the polyester material. However, this method cannot effectively increase the proportion of recycled polyester material in matte polyester film, and therefore the final matte polyester film product cannot meet environmental protection requirements. In other words, there is a definite limit to the proportion of recycled polyester in existing matte polyester film, which needs to be resolved. Summary of the Invention [Problem to be solved by the invention]

[0005] There are clear limitations on the proportion of recycled polyester in existing matte polyester films that need to be addressed. [Means for solving the problem]

[0006] The present disclosure provides a matte polyester film and a method for producing the same that solves technical problems.

[0007] The present disclosure provides a method for producing a matte polyester film. The method includes the following steps: providing recycled polyester material; physically regenerating a portion of the recycled polyester material to form physical recycled polyester chips having a first intrinsic viscosity; chemically regenerating another portion of the recycled polyester material to form chemical recycled polyester chips having a second intrinsic viscosity lower than the first intrinsic viscosity; mixing the matte recycled polyester chips, the physical recycled polyester chips, and the chemical recycled polyester chips according to a predetermined intrinsic viscosity to form a polyester masterbatch material; and melting and extruding the polyester masterbatch material to obtain a matte polyester film having the predetermined intrinsic viscosity. The predetermined intrinsic viscosity of the matte polyester film is 0.40 dL / g to 0.75 dL / g, has an acid value of 10 mgKOH / g to 80 mgKOH / g, has a surface roughness (Ra) of 100 nm to 400 nm, and has a coefficient of friction of 0.2 to 0.6.

[0008] The present disclosure provides a matte polyester film. The matte polyester film is formed by mixing, dissolving, and extruding a physically recycled polyester resin and a chemically recycled polyester resin according to a predetermined intrinsic viscosity. The matte polyester film has a predetermined intrinsic viscosity of 0.40 dL / g to 0.75 dL / g, an acid value of 10 mgKOH / g to 80 mgKOH / g, a surface roughness (Ra) of 100 nm to 400 nm, and a coefficient of friction of 0.2 to 0.6.

[0009] In one embodiment, the content of isophthalic acid in the matte polyester film is 0.7 mol% to 4.0 mol%, based on 100 mol% of the total weight of the matte polyester film. The storage modulus of the matte polyester film measured at 150±2°C and 10 Hz is 4.2×10 9 dyne / cm 2 ~6.8×10 9 dyne / cm 2 is.

[0010] In one embodiment, the matte polyester film has a haze of 15% to 95%, and the matte polyester film has a visible light transmittance of 60% or greater.

[0011] In one embodiment, the content of biomass-derived ethylene glycol in the matte polyester film is 5 wt% or less, based on 100 wt% of the total weight of the matte polyester film.

[0012] To solve the above technical problems, the technical solution applied in the present disclosure is to provide a matte polyester film, which has a predetermined intrinsic viscosity of 0.40 dL / g to 0.75 dL / g, an acid value of 10 mg KOH / g to 80 mg KOH / g, a surface roughness (Ra) of 100 nm to 400 nm, and a coefficient of friction of 0.2 to 0.6.

[0013] In one embodiment, the content of isophthalic acid in the matte polyester film is 0.7 mol% to 4.0 mol%, based on 100 mol% of the total weight of the matte polyester film. The storage modulus of the matte polyester film measured at 150±2°C and 10 Hz is 4.2×10 9 dyne / cm 2 ~6.8×10 9 dyne / cm 2 is.

[0014] In one embodiment, the matte polyester film has a haze of 15% to 95%, and the matte polyester film has a visible light transmittance of 60% or greater.

[0015] In one embodiment, the content of biomass-derived ethylene glycol in the matte polyester film is 5 wt% or less, based on 100 wt% of the total weight of the matte polyester film. [Effects of the Invention]

[0016] One of the useful effects of the present disclosure is that the matte polyester film and the manufacturing method thereof according to the present disclosure can achieve a high proportion of recycled polyester masterbatch material by using a technical solution such as "mixing matte recycled polyester chips, physically recycled polyester chips, and chemically recycled polyester chips according to a predetermined intrinsic viscosity to form a polyester masterbatch material," thereby adjusting the polyester masterbatch material to have a predetermined intrinsic viscosity suitable for film extrusion processing.

[0017] For a better understanding of the features and technical contents of the present disclosure, please refer to the following detailed description of the present disclosure and the drawings, however, the drawings are for reference and explanation purposes only and should not be used to limit the present disclosure. [Brief explanation of the drawings]

[0018] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the present disclosure and, together with the detailed description, serve to explain the principles of the disclosure.

[0019] [Figure 1] FIG. 1 is a schematic flow chart of a method for producing a matte polyester film of the present disclosure.

[0020] [Figure 2]FIG. 2 is a schematic representation of the molecular weight distribution of the polyester masterbatch material of the present disclosure.

[0021] [Figure 3] FIG. 3 shows the test results of the storage modulus of a matte polyester film according to one embodiment of the present disclosure (test conditions: film thickness 50 microns, test direction MD).

[0022] [Figure 4] FIG. 4 shows the storage modulus test results of a matte polyester film according to one embodiment of the present disclosure (test conditions: film thickness 50 microns, test direction TD). DETAILED DESCRIPTION OF THE INVENTION

[0023] The following are specific embodiments for explaining the implementation of the "matte polyester film and manufacturing method thereof" disclosed in the present disclosure. Those skilled in the art can understand the advantages and effects of the present disclosure from the contents disclosed herein. The present disclosure may be implemented or applied in other different specific embodiments. Furthermore, various details in the present specification may be modified and changed based on different perspectives and applications without departing from the concept of the present disclosure. Furthermore, the drawings in the present disclosure are merely schematic diagrams and are not drawn to actual scale. The following embodiments will explain the technical content related to the present disclosure in detail, but the disclosed content is not intended to limit the technical scope of the present disclosure. Furthermore, the term "or" used in the present specification may include any one or combination of multiple related listed items depending on the actual situation.

[0024] (Matte polyester film manufacturing method)

[0025] One of the objectives of the present disclosure is to increase the proportion of recycled polyester materials in matte polyester films, so that matte polyester film products can meet environmental protection requirements.

[0026] To achieve the above objective, refer to FIG. 1. One embodiment of the present disclosure provides a manufacturing method for a matte polyester film that effectively increases the proportion of recycled polyester material in the matte polyester film and provides a matte polyester film with good processability. The manufacturing method for the matte polyester film includes steps S110 to S150. The order of the steps and the actual operation method described in this embodiment may be adjusted as needed and are not limited to those described in this embodiment.

[0027] Step S110 includes providing a recycled polyester material.

[0028] To obtain reusable recycled polyester materials, a method for recycling polyester materials includes collecting various types of waste polyester materials and sorting them according to the type, color, and use of the waste polyester. The waste polyester materials are then compressed and packaged. The packaged waste polyester materials are then transported to a waste disposal site. In this embodiment, the waste polyester materials are recycled PET bottles (r-PET), although the present disclosure is not limited thereto.

[0029] The polyester material recycling method further includes removing other objects (e.g., bottle caps, labels, and adhesives) on the waste polyester material. The waste polyester material is then pulverized by physical and mechanical means. After that, bottle necks, liners, and bottle bodies of different materials are separated by flotation. Furthermore, the pulverized waste polyester material is dried to obtain processed recycled polyester material, such as bottle pieces from recycled PET bottles (r-PET), which facilitates subsequent thin film manufacturing processes.

[0030] In other application embodiments of the present disclosure, the recycled polyester material may be, for example, directly purchased treated recycled polyester material.

[0031] As used herein, the terms "polyester," "polyester material," and the like refer to any type of polyester, particularly aromatic polyesters, and specifically herein refers to polyesters derived from the copolymerization of terephthalic acid and ethylene glycol, i.e., polyethylene terephthalate (PET).

[0032] The polyester may be, for example, polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), or polyethylene naphtharate (PEN). In this embodiment, the polyester is preferably polyethylene terephthalate or polytrimethylene terephthalate. Furthermore, copolymers, particularly copolymers obtainable using two or more dicarboxylic acids and / or two or more diol components, may also be used.

[0033] In one embodiment of the present disclosure, the r-PET bottle pieces contain isophthalic acid (IPA) as a dibasic acid unit. Therefore, the final matte polyester film also contains isophthalic acid. Specifically, the content of isophthalic acid in the matte polyester film is 0.5 mol% to 5 mol% based on 100 mol% of the total weight of the matte polyester film.

[0034] In one embodiment of the present disclosure, the r-PET bottle pieces contain biomass-derived ethylene glycol as a diol unit. Therefore, the final matte polyester film also contains biomass-derived ethylene glycol. In particular, the content of biomass-derived ethylene glycol in the matte polyester film is 5 wt% or less based on 100 wt% of the total weight of the matte polyester film. In addition, the content of radioactive elements (C 14The biomass-derived carbon content, as measured by the IEC 61001-2002, is less than 5%.

[0035] In one embodiment of the present disclosure, the r-PET bottle pieces contain a metal catalyst, so that the final matte polyester film also contains a metal catalyst. Specifically, the metal catalyst is at least one selected from the group consisting of antimony (Sb), germanium (Ge), and titanium (Ti). Based on the total weight of the matte polyester film (100 wt%), the content of the metal catalyst in the matte polyester film is 0.0003 wt% to 0.04 wt%.

[0036] Step S120 involves physically regenerating a portion of the recycled polyester material to obtain physically recycled polyester chips. The physically recycled polyester chips have a first intrinsic viscosity. In this embodiment, the first intrinsic viscosity of the physically recycled polyester chips is generally 0.60 dL / g or more. Preferably, the first intrinsic viscosity is 0.65 dL / g to 0.90 dL / g. More preferably, the first intrinsic viscosity is 0.65 dL / g to 0.80 dL / g.

[0037] Specifically, the manufacturing process for physical recycled polyester chips involves pulverizing a portion of recycled polyester material (e.g., r-PET bottle fragments) by physical mechanical means to reduce the time and energy consumption required to dissolve the recycled polyester material. The pulverized recycled polyester material is then melted, thereby bringing the recycled polyester material into a molten state. The molten recycled polyester material is then filtered using a first screen to remove solid impurities from the recycled polyester material. Finally, the filtered recycled polyester material is extruded and pelletized to form physical recycled polyester chips.

[0038] In other words, the recycled polyester material is reformed by cutting, dissolving, filtering, extruding, etc., in order to prepare a plurality of physical recycled polyester chips by rearranging the polyester molecules in the original recycled polyester material.

[0039] In the physical recycling process, the polyester molecules of the recycled polyester material are only rearranged, not reorganized, so the components originally present in the recycled polyester material (such as metal catalysts, slip agents, or copolymerized monomers) still exist in the recycled polyester material, and therefore the final matte polyester film also contains these components. Furthermore, various properties of the recycled polyester material itself are also maintained in the physically recycled polyester chips.

[0040] Since the molecular weight of the recycled polyester material does not change significantly during the physical recycling process, the recycled polyester material has a relatively high viscosity in a dissolved state and is difficult to flow, so if a screen with an insufficient mesh size is used, the filtration efficiency will easily become insufficient.

[0041] In this embodiment, to obtain a good filtering effect, the mesh diameter of the first screen is preferably 10 microns to 100 microns. In other words, the first screen can block solid impurities with a particle size larger than the mesh diameter, but the present disclosure is not limited thereto.

[0042] It is noted that different film-forming processes have different suitable intrinsic viscosity ranges. Generally, physically recycled polyester chips (physically recycled polyester resins) obtained by physical recycling have high intrinsic viscosities (0.60 dL / g or more). When only physically recycled polyester chips (physically recycled polyester resins) are used, the polyester masterbatch material is only suitable for bottle blowing and spinning processes, but not for film extrusion processes.

[0043] Solid-state polymerization may be used to adjust the intrinsic viscosity of the physically recycled polyester chips. However, the solid-state polymerization method can only be used to increase the intrinsic viscosity of the physically recycled polyester chips, and cannot be used to decrease the intrinsic viscosity of the physically recycled polyester chips.

[0044] To solve the above problems, in the present disclosure, chemically recycled polyester chips (chemically recycled polyester resin) with a low intrinsic viscosity (0.65 dL / g or less) are prepared by the chemical recycling step in step S130. Therefore, by simultaneously using both physically recycled polyester chips and chemically recycled polyester chips and adjusting the ratio of the physically recycled polyester chips and chemically recycled polyester chips, the intrinsic viscosity of the polyester masterbatch material can be adjusted, making the polyester masterbatch material suitable for film extrusion processing.

[0045] Step S130 includes chemically regenerating another portion of the recycled polyester to obtain chemically recycled polyester chips. The chemically recycled polyester chips have a second intrinsic viscosity, which is less than the first intrinsic viscosity of the physically recycled polyester chips. In this embodiment, the second intrinsic viscosity of the chemically recycled polyester chips is generally 0.65 dL / g or less. Preferably, the second intrinsic viscosity is 0.40 dL / g to 0.65 dL / g. More preferably, the second intrinsic viscosity is 0.50 dL / g to 0.65 dL / g.

[0046] Specifically, the process for producing chemically recycled polyester chips involves cutting or crushing another portion of recycled polyester material (such as r-PET bottle fragments) to reduce the time and energy required to depolymerize the recycled polyester material. The cut or crushed recycled polyester material is then placed in a chemical depolymerization solution to depolymerize the polyester material, forming a masterbatch material mixture. The masterbatch material mixture is then filtered using a second screen to remove solid impurities in the recycled polyester material, thereby reducing the concentration of non-polyester impurities in the masterbatch material mixture.

[0047] Next, the masterbatch material mixture filtered through the second screen is subjected to an esterification reaction, during which inorganic additives or copolymer monomers are added. Finally, under specific reaction conditions, the monomers and / or oligomers in the masterbatch material mixture are repolymerized and pelletized to obtain chemically recycled polyester chips. In particular, the liquid temperature of the chemical depolymerization solution is, for example, 160°C to 250°C, but the present disclosure is not limited thereto. Furthermore, the mesh diameter of the second screen is smaller than the mesh diameter of the first screen.

[0048] The chemical depolymerization solution may cause chain scission in the polyester molecules in the recycled polyester material to achieve the depolymerization effect, and further obtain a polyester composition having short molecular chains and an ester monomer consisting of one dibasic acid unit and two diol units, such as bis(2-hydroxyethyl) terephthalate (BHET). That is, the molecular weight of the masterbatch material mixture is equal to or less than the molecular weight of the recycled polyester material.

[0049] In this embodiment, the chemical depolymerization solution may be, for example, a solution of water, methanol, ethanol, ethylene glycol, diethylene glycol, or a combination thereof, but the present disclosure is not limited thereto. For example, water is used for hydrolysis, and methanol, ethanol, ethylene glycol, or diethylene glycol is used for alcoholysis.

[0050] Also, unlike the physical regeneration step, the chemical regeneration step involves "depolymerization and repolymerization of polyester molecules in recycled polyester materials," in which polyester molecules are depolymerized into molecules of smaller molecular weight and then repolymerized into new polyester resin.

[0051] In another embodiment of the present disclosure, the method for preparing chemically recycled polyester chips is not limited to those described in the above embodiment, and the chemically recycled polyester chips may also be prepared by hydrolysis or supercritical fluid methods. The hydrolysis method is performed on recycled polyester material in an alkaline solution, and by adjusting a specific temperature and pressure and irradiating with microwave radiation, the polyester molecules are completely decomposed into monomers. The supercritical fluid method decomposes recycled polyester material in supercritical fluid methanol into small amounts of monomers and oligomers. In particular, the yield of monomers and oligomers is affected by the reaction temperature and reaction time.

[0052] Furthermore, chemical recycling methods may depolymerize recycled polyester materials into monomers with smaller molecular weights, and therefore impurities originally present in recycled polyester materials (such as r-PET bottle fragments) (e.g., colloidal impurities or other non-polyester impurities) may be more easily removed by filtration compared to physical recycling methods.

[0053] In addition, the chemical recycling process can reduce the molecular weight of the recycled polyester material (e.g., form polyester compositions and compound monomers with shorter molecular chains), so that the recycled polyester material has lower viscosity and better flow properties after being depolymerized. Therefore, the chemical recycling process may employ a screen with a smaller mesh size to remove impurities with smaller particle sizes in the polyester material.

[0054] In this embodiment, in order to obtain a good filtering effect, the mesh diameter of the second screen is preferably 1 micron to 10 microns. In other words, the second screen blocks solid impurities having a particle size larger than the mesh diameter, but the present disclosure is not limited thereto.

[0055] In terms of filtering out solid impurities, the physical regeneration step can filter out and recycle solid impurities with large particle sizes in the polyester material, while the chemical regeneration step can filter out and recycle solid impurities with small particle sizes in the polyester material, so the product quality of the matte polyester film can be effectively improved.

[0056] Furthermore, the chemically recycled polyester chips produced by the chemical regeneration step generally have a low intrinsic viscosity, which is easy to control and can be adjusted to be lower than the intrinsic viscosity of the physically recycled polyester chips.

[0057] Step S140 includes mixing the matte recycled polyester chips, the physically recycled polyester chips, and the chemically recycled polyester chips according to a predetermined intrinsic viscosity to produce a polyester masterbatch material.

[0058] Thus, the intrinsic viscosity of the polyester masterbatch material is suitable for the film-forming process. Specifically, the intrinsic viscosity of the polyester masterbatch material is 0.50 dL / g to 0.8 dL / g. Preferably, the intrinsic viscosity of the polyester masterbatch material is 0.50 dL / g to 0.60 dL / g. Furthermore, the final matte polyester film has a predetermined intrinsic viscosity, which is 0.50 dL / g to 0.75 dL / g. Preferably, the predetermined intrinsic viscosity is 0.50 dL / g to 0.60 dL / g.

[0059] More specifically, the matte recycled polyester chips, the physically recycled polyester chips, and the chemically recycled polyester chips are mixed together in a weight ratio according to a predetermined intrinsic viscosity, so that the mixed matte recycled polyester chips, the physically recycled polyester chips, and the chemically recycled polyester chips have an intrinsic viscosity suitable for film formation processing.

[0060] The matte recycled polyester masterbatch material includes a matte additive, the matte additive being at least one material selected from the group consisting of silica particles, calcium carbonate particles, alumina particles, and talc particles. Specifically, the matte additive has a particle size of 0.1 μm to 10 μm. The content of the matte additive is 0.1 weight percent to 20 weight percent, based on 100 weight percent of the total weight of the matte polyester film.

[0061] The matte recycled polyester chips may be prepared by a physical recycling step or a chemical recycling step. In other words, the matte recycled polyester chips include at least one of physically recycled matte polyester chips and chemically recycled matte polyester chips.

[0062] Specifically, a method for producing physically recycled matte polyester chips includes melting a portion of recycled polyester material to obtain a first melt mixture. A matte additive is added to the first melt mixture to form a second melt mixture. The second melt mixture is reformed to obtain physically recycled matte polyester chips. In one embodiment of the present disclosure, for example, the first melt mixture is first filtered through a first screen, and then a matte additive is added to obtain a second melt mixture. Furthermore, by adding the matte additive to the physically recycled matte polyester chips, the intrinsic viscosity of the physically recycled matte polyester chips is reduced. In one embodiment of the present disclosure, the intrinsic viscosity of the physically recycled matte polyester chips is 0.58 dL / g to 0.72 dL / g.

[0063] Specifically, a method for producing chemically recycled matte polyester chips includes depolymerizing another portion of recycled polyester material to obtain a first oligomer mixture. A matte additive is added to the first oligomer mixture to form a second oligomer mixture. The second oligomer mixture is then repolymerized to obtain chemically recycled matte polyester chips. In one embodiment of the present disclosure, for example, the first oligomer mixture is first filtered through a second screen, and then a matte additive is added to form a second oligomer mixture. The addition of the matte additive to the chemically recycled matte polyester chips reduces their intrinsic viscosity. In one embodiment of the present disclosure, the intrinsic viscosity of the chemically recycled matte polyester chips is 0.45 dL / g to 0.58 dL / g.

[0064] To increase the proportion of recycled polyester material, various regenerated polyester chips all have suitable ranges of uses.

[0065] In terms of a predetermined weight ratio, the amount of physically recycled polyester chips is preferably 50 to 95 parts by weight, more preferably 60 to 80 parts by weight, based on 100 parts by weight of the polyester masterbatch material (i.e., all polyester chips). The amount of chemically recycled polyester chips is between 5 and 50 parts by weight, preferably 20 to 40 parts by weight, although the present disclosure is not limited thereto.

[0066] In a preferred embodiment, the amount of physically recycled polyester chips is greater than the amount of chemically recycled polyester chips, although the present disclosure is not limited in this respect.

[0067] Step S150 includes melting and then extruding a polyester masterbatch material to form a matte polyester film, particularly, the matte polyester film having a predetermined intrinsic viscosity.

[0068] In the matte polyester film, the physically recycled polyester chips (including the physically recycled matte polyester chips) form the physically recycled polyester resin, and the chemically recycled polyester chips (including the chemically recycled matte polyester chips) form the chemically recycled polyester resin, and the matte additive in the matte recycled polyester chips is evenly dispersed in the physically recycled polyester resin and the chemically recycled polyester resin.

[0069] According to the mixing ratio in step S140, the content of the physically recycled polyester resin is preferably 50 wt% to 95 wt%, more preferably 60 wt% to 80 wt%, based on the total weight of the matte polyester film (100 wt%). The content of the chemically recycled polyester resin is preferably 5 wt% to 50 wt%, more preferably 20 wt% to 40 wt%, and the content of the matte additive is 0.1 wt% to 20 wt%.

[0070] The total content of the physically recycled polyester resin and the chemically recycled polyester resin is 55 wt% to 100 wt%, and the total content is more preferably 70 wt% to 100 wt%.

[0071] According to the above configuration, the method for producing a matte polyester film according to the present invention can be carried out using a high proportion of recycled polyester material without adding any additional virgin polyester resin, or only a small amount of virgin polyester resin needs to be added. For example, in one embodiment of the present disclosure, the amount of virgin polyester resin is typically 50 parts by weight or less, preferably 30 parts by weight or less, and more preferably 10 parts by weight or less.

[0072] In one embodiment of the present disclosure, the physically recycled polyester chips have a first acid value, and the chemically recycled polyester chips have a second acid value, the second acid value being greater than the first acid value. Specifically, the first acid value is 10 mg KOH / g to 40 mg KOH / g, and the second acid value is 20 mg KOH / g to 70 mg KOH / g.

[0073] More specifically, referring to Figure 2, the physically recycled polyester chips have a first molecular weight distribution 1, and the chemically recycled polyester chips have a second molecular weight distribution 2, the distribution range of which is wider than the distribution range of which is the first molecular weight distribution 1.

[0074] Furthermore, by mixing the physical recycled polyester chips and the chemically recycled polyester chips, the polyester masterbatch material (matt recycled polyester chips, physical recycled polyester chips, and chemically recycled polyester chips) has a third molecular weight distribution 3, and the distribution range of the third molecular weight distribution 3 is between the first molecular weight distribution 1 and the second molecular weight distribution 2.

[0075] More specifically, the molecular weight distribution of chemically recycled polyester chips is broad, which can contribute to the productivity of the film-forming process, but the physical properties (mechanical properties, etc.) of matte polyester films produced using only chemically recycled polyester chips are poor. Furthermore, the production cost of chemically recycled polyester chips is high.

[0076] The molecular weight distribution of physically recycled polyester chips is narrow, which is unfavorable in terms of productivity in the film-forming process, but it can produce matte polyester films with high mechanical properties and good physical properties. In other words, it is not ideal to completely use physical or chemical recycling.

[0077] A feature of the method for producing a matte polyester film according to one embodiment of the present disclosure is that by simultaneously using physically recycled polyester chips and chemically recycled polyester chips, the productivity of the film formation process can be improved, the physical properties of the matte polyester film can be improved, and the production cost of the matte polyester film can be reduced.

[0078] (Matte polyester film)

[0079] The above is a method for producing a matte polyester film according to one embodiment of the present disclosure. Hereinafter, a matte polyester film according to one embodiment of the present disclosure will be described. In this embodiment, the matte polyester film is formed by the above-described production method, but the present disclosure is not limited thereto.

[0080] The matte polyester film material includes a physically recycled polyester resin, a chemically recycled polyester resin, and a matte additive. The physically recycled polyester resin is formed from physically recycled polyester chips, and the physically recycled polyester chips have a first intrinsic viscosity. The chemically recycled polyester resin is formed from chemically recycled polyester chips, and the chemically recycled polyester chips have a second intrinsic viscosity that is less than the first intrinsic viscosity. The matte additive is dispersed between the chemically recycled polyester resin and the physically recycled polyester resin.

[0081] The physical recycled polyester chips and the chemically recycled polyester chips are mixed according to a predetermined target intrinsic viscosity, so that the resulting matte polyester film can have a predetermined intrinsic viscosity.

[0082] In an embodiment of the present disclosure, the first intrinsic viscosity of the physically recycled polyester chips is 0.60 dL / g or less, the second intrinsic viscosity of the chemically recycled polyester chips is 0.65 dL / g or less, and the predetermined intrinsic viscosity is 0.40 dL / g to 0.75 dL / g.

[0083] In a preferred embodiment of the present disclosure, the first intrinsic viscosity of the physically recycled polyester chips is 0.65 dL / g to 0.80 dL / g, the second intrinsic viscosity of the chemically recycled polyester chips is 0.50 dL / g to 0.65 dL / g, and the matte polyester film has a predetermined intrinsic viscosity of 0.50 dL / g to 0.60 dL / g.

[0084] In one embodiment of the present disclosure, the matte polyester film has an acid value of 10 mgKOH / g to 80 mgKOH / g, and preferably has an acid value of 40 mgKOH / g to 70 mgKOH / g.

[0085] The method for determining the acid number range of a matte polyester film is by titration, which is performed in accordance with ASTM standard test method D7409-15.

[0086] When the acid value of the matte polyester film is in the range of 10 mgKOH / g to 80 mgKOH / g, the matte polyester film has heat resistance and hydrolysis resistance under the condition of low acid value.

[0087] The recycled polyester material is characterized in that multiple physical recycled polyester chips and multiple chemical recycled polyester chips are obtained by recycling and pelletizing the recycled polyester material. In particular, the recycled polyester material is r-PET bottle fragments.

[0088] According to the above configuration, the matte polyester film satisfies the following conditions: (i) the content of isophthalic acid in the matte polyester film is 0.7 mol% to 4.0 mol%, based on 100 mol% of the total weight of the matte polyester film; (ii) the content of biomass-derived ethylene glycol in the matte polyester film is 5 wt% or less, based on 100 wt% of the total weight of the matte polyester film; (iii) the haze of the matte polyester film is 15% to 95%; (iv) the visible light transmittance of the matte polyester film is 60%, preferably 80% or more; (v) the surface roughness (Ra) of the matte polyester film is 100 nm to 400 nm (the surface roughness is measured in accordance with DIN EN ISO4287 / 4288); and (vi) the friction coefficient of the matte polyester film is 0.2 to 0.6.

[0089] The method for measuring the coefficient of friction of matte polyester film is based on ASTM D1894.

[0090] In an embodiment of the present disclosure, the storage modulus of the matte polyester film measured at 150±2°C and 10 Hz is 4.2×10 9 dyne / cm 2 ~6.8×10 9 dyne / cm 2 and preferably 4.2 x 10 9dyne / cm 2 ~6.6×10 9 dyne / cm 2 The storage modulus of the matte polyester film is the average value of the storage modulus of the matte polyester film in the MD and TD directions measured using a dynamic viscoelasticity measuring device. Specific measurement results are shown in Figures 3 and 4, but the present disclosure is not limited thereto.

[0091] (Effects of the embodiment)

[0092] One of the beneficial effects of the present disclosure is that, with respect to the matte polyester film and the manufacturing method thereof provided by the present disclosure, through the technical solution of "mixing matte recycled polyester chips, physically recycled polyester chips, and chemically recycled polyester chips according to a predetermined intrinsic viscosity to form a polyester masterbatch material," the polyester masterbatch material can be adjusted to have a predetermined intrinsic viscosity suitable for film extrusion processing, thereby achieving a higher proportion of recycled polyester masterbatch material.

[0093] The above disclosure is merely a preferred embodiment of the present disclosure and does not limit the technical scope of the present disclosure. Therefore, all equivalent technical modifications obtained using the contents of the specification and drawings of the present disclosure are all encompassed within the technical scope of the present disclosure. [Industrial Applicability]

[0094] The matte polyester film and the manufacturing method thereof may be applied to the field of matte polyester films.

Claims

1. A matte polyester film having a predetermined intrinsic viscosity of 0.40 dL / g to 0.75 dL / g, an acid value of 10 mgKOH / g to 80 mgKOH / g, a surface roughness (Ra) of 100 nm to 400 nm, and a coefficient of friction of 0.2 to 0.

6.

2. The content of isophthalic acid in the matte polyester film is between 0.7 mol% and 4.0 mol%, based on 100 mol% of the total weight of the matte polyester film; The storage modulus of the matte polyester film measured at 150±2° C. and 10 Hz was 4.2×10 ９ dyne / cm ２ ~6.8 x 10 ９ dyne / cm ２ That is, 2. The matte polyester film according to claim 1.

3. the matte polyester film has a haze of 15% to 95%; The matte polyester film has a visible light transmittance of 60% or more.

2. The matte polyester film according to claim 1.

4. 2. The matte polyester film according to claim 1, wherein the content of biomass-derived ethylene glycol in the matte polyester film is 5 wt % or less, based on 100 wt % of the total weight of the matte polyester film.

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